The specificity and the ability ofAspergillusferuloyl esterase to releasep‐coumaric acid from complex cell walls of oat hulls

Abstract

Abstractp‐Coumaric acid (4‐hydroxycinnamic) and ferulic acid (4‐hydroxy‐3‐methoxycinnamic), two major hydroxycinnamic acids found in the complex cell walls of oat hulls, act as cross‐linking agents between lignin and polysaccharides or between polysaccharides. As such, they are inhibitory to the biodegradation of cell walls by microorganisms. A previous study showed thatAspergillusferuloyl esterase withTrichodermaxylanase was able to break the ester linkage between ferulic acid and the attached sugar, releasing ferulic acid from the cell wall. The objective of this study was to investigate the specificity and the ability ofAspergillusferuloyl esterase to releasep‐coumaric acid from oat hulls. The results show there was no extensive release ofp‐coumaric acid in both the absence and presence ofTrichodermaxylanase byAspergillusferuloyl esterase. This indicates a specificity ofAspergillusferuloyl esterase, which is more active only on esters of certain hydroxycinnamic acids; in this case,Aspergillusferuloyl esterase will only sufficiently break the ester‐linked feruloyl group but not thep‐coumaroyl group in the complex cell walls of oat hulls. Copyright © 2004 Society of Chemical Industry